JRC JMR-92 Series Field Service Manual page 69

PSU Input Section
To drive PSU, AC power input, DC power input, and control signal inputs are required.
The ship's AC power supply is input to each stabilized power supply circuit via a circuit breaker
and a line filter, and generates the required voltage. If only DC power (24Vdc) is input to PSU, It
will not generate 48Vdc. Each power supply circuit is a highly efficient switching power supply
circuit.
PSU is equipped with overvoltage protection. If the input voltage exceeds the set upper limit, the
circuit breaker trips to prevent the excessive voltage from being applied to the system. It is not
necessary to change input voltage setting of 100 or 220Vac because PSU has a wide range AC
input.
Control signals are used to control the outputs which are 100-220Vac, 48Vdc, 24Vdc(M+, M-),
24Vdc(1A, 2A), 24Vdc(MNU), 24Vdc(CCU). They are open collector signals.
The control signals are the follows:
N_24V_ON
N_MTR_ON
N_MNU_ON
PSU Output Section
The Outputs of PSU are 100-220Vac, 48Vdc, 24Vdc (M+, M-), 24Vdc (1A, 2A), 24Vdc (MNU),
24Vdc (CCU), 12Vdc (P+12V), and alarm signals.
12Vdc (P+12V) power supply operates even when the operating unit is turned off. This power
supply is used in functions such as the control circuit of the power supply circuit and the
interswitch control function.
When the power switch of OPU is turned on, PSU used in the system is activated and outputs
power at the following voltages:
24Vdc (MNU)
24Vdc (CCU)
100-220Vac and 48Vdc power supply for the AC scanner power are output independently from
the power for the system itself. When N_MTR_ON the scanner unit power control signal is input
from the interswitch unit, 100-220Vac and 48Vdc power supply come on. Where the interswitch
function is not used, these actions are linked to the power switch of OPU. 48Vdc power supply is
used in the internal control circuit of the AC scanner unit and in the transmitter-receiver unit. It is
the same for DC scanner power. In DC scanner, 24Vdc (M+, M-) and 24Vdc (1A, 2A) are used.
Each power supply output has output overcurrent protection, so that if there is a short circuit of
the load or the rated output is exceeded, protective functions are activated and shut down the
output.
The system is equipped with a function to provide notification that the ship's AC power supply is
shut off. Connecting the system to the ship's battery (24V) makes it possible for an alarm to be
sounded from the OPU when the ship's AC power supply is shut down.
: CCU power control signal
: Scanner unit power control signal
: Monitor unit power control signal
: for Monitor Unit
: for Central Control Unit
2-11 Chapter 2 System Configuration